U.S. Pat. No. 4,770,641, granted Sep. 13, 1988, describes a conductive gel interconnection apparatus useful to interconnect pin grid arrays or other components having closely spaced conductors with the conductive traces of circuits such as on printed circuit boards. The patent teaches a particular type of conductive gel which, while conforming to housing cavities in which it is used, is sufficiently coherent and viscous that it will not flow from the cavity location and will maintain its original shape when removed from contact with a component.
U.S. patent application Ser. No. 07/613,195 filed Nov. 15, 1990 is drawn to an area array connector utilizing conductive gel in conjunction with a deformable elastomer defining the gel cavities. The elastomer is compressed by the component against a circuit and is caused to flow to effect a gel interconnection. U.S. patent application Ser. No. 07/698,744, and assigned to the assigned hereof, represents an alternative and improvement upon this latter application by utilizing a sheet of material of a relatively low thermal coefficient of expansion containing inserts which house gel defining contact locations. This latter application facilitates interconnection of large numbers of contacts spread in an array fashion and minimizes tolerance problems caused by differential expansion and contraction of the connector relative to the components and circuits being interconnected.
In these latter applications, an interconnection is effected by compression of an elastomer to cause a gel contained in a cavity in the elastomer to flow and interconnect to opposing contact surfaces. The bulk of the force required to cause such interconnection is due to the compression of the elastomer, the relative hardness thereof, and very little due to the force required to cause the gel to flow and make contact. The forces required per contact are, in the foregoing applications, relatively low compared to traditional contacts but are nevertheless substantial when the numbers of contacts in an array exceed 100 and, as is frequently the case, many hundreds in a single connector array.
The present invention has as an object the provision of a low-force, high-density connector array wherein large numbers of contacts are simultaneously interconnected. The invention has as a further object the provision of an interconnection wherein the force of closure and deformation of a gel is due to the characteristics of the gel itself and not the elastomer carrying the gel. The invention has as yet a further object the provision of a multiple contact array connector wherein large numbers of closely spaced gel contacts can be laid down by standard silkscreen and/or stenciling processes to reduce the cost of manufacture while facilitating the manufacture of a precision part.